Mega

Mega (symbol M) is a SI prefix in the SI system of units denoting a factor of 10⁶, i.e. one million; 1 000 000.

Confirmed in 1960, it comes from the Greek μέγας, meaning great.

For example, 1 MW (megawatt) = 1 000 000 watts = 1 000 kilowatts.

Other common examples of usage:

• one megaton [of TNT] (a unit often used in measuring the explosive power of nuclear weapons) is 1,000,000 tTNT.
• Megahertz - frequency of electromagnetic radiation for radio and televion broadcasting, GSM, etc. 1 MHz = 1 000 000 Hz

In computing, mega can sometimes denote 1,048,576 (2²⁰) of information units (example: a megabyte, a megaword), but can denote 1 000 000 (10⁶) of other quantities, for example, transfer rates: 1 megabit/s = 1 000 000 bit/s.

The prefix mebi has been suggested as an alternative for 2²⁰ to avoid ambiguity, but is yet to be widely used.

See also

• SI prefix
• Binary prefix
• Mebibyte